Problem: Solve for $x$ : $4x^2 + 24x + 36 = 0$
Dividing both sides by $4$ gives: $ x^2 + {6}x + {9} = 0 $ The coefficient on the $x$ term is $6$ and the constant term is $9$ , so we need to find two numbers that add up to $6$ and multiply to $9$ The number $3$ used twice satisfies both conditions: $ {3} + {3} = {6} $ $ {3} \times {3} = {9} $ So $(x + {3})^2 = 0$ $x + 3 = 0$ Thus, $x = -3$ is the solution.